Free Online Calculators, Converters, PDF & Image Tools
Quick tools for everyday conversions and calculations. Free · No sign-up · Runs in your browser. US units are shown first, with metric alongside.
Unit converters
- Length Converter (cm to inches, feet)Convert inches, feet, yards and miles to centimeters, meters and kilometers — with a height chart in feet and inches.
- Weight Converter (kg to lbs)Convert kilograms to pounds and ounces, pounds to kg, stone, grams and US tons — with body-weight charts.
- Temperature Converter (°F to °C)Convert Fahrenheit to Celsius and Kelvin with the formula, plus body-temperature and oven-temperature charts.
- Area Converter (sq ft to m², acres)Convert square feet, square yards, acres and square miles to square meters, hectares and square kilometers.
- Volume Converter (liters to gallons, cups)Convert liters, mL and cubic meters to US gallons, quarts, pints, cups, fluid ounces, tablespoons and teaspoons.
- Speed Converter (mph to km/h)Convert miles per hour to kilometers per hour, knots, meters per second and feet per second, with speed-limit charts.
- Data Storage Converter (GB to MB, TB)Convert bits, bytes, KB, MB, GB, TB and PB in decimal (1000) or binary (1024) units, and estimate download time.
Everyday calculators
- Date Calculator (days between dates)Count the days between two dates, or add and subtract days from a date — with weeks and months.
- Days Until Calculator (countdown)Count down the days until a birthday, holiday, exam or trip — or the days since a past date.
- Age Calculator (by date of birth)Calculate exact age in years, months and days from a date of birth, plus days until the next birthday.
- Word Counter & Character CountCount words, characters with and without spaces, sentences and paragraphs, plus reading and speaking time.
- Time Zone ConverterConvert a time between any two cities and see the same moment in 30 major cities, with daylight saving time applied.
- BMI Calculator (lbs & ft or kg & cm)Calculate body mass index in US units or metric, with WHO adult categories and a healthy weight range for your height.
- Percentage Calculator (percent off, % change)Find X% of a number, what percent one number is of another, percentage increase or decrease, and sale prices.
- Time Calculator (add hours & minutes)Add and subtract hours, minutes and seconds, find hours between two times with a lunch break, overnight shifts included.
- Tip Calculator (split the bill)Tip at 15, 18, 20% or any rate, on the pre-tax amount if you like, split between friends and rounded up.
- Concrete Calculator (yards & bags)Cubic yards and 40, 60 or 80 lb bags for slabs, post holes and footings, in feet and inches.
School & math
- Final Grade CalculatorWhat do I need on my final? Enter your current grade, target and final exam weight.
- Weighted Grade CalculatorWeighted grade calculator with categories (homework, quizzes, exams) and missing assignments.
- Fraction Calculator (with steps)Add, subtract, multiply and divide fractions and mixed numbers, with step-by-step work.
- Percent Change Calculator (increase / decrease)Percentage increase or decrease between two numbers, percent difference, and increasing a number by a percent.
- Reverse Percentage CalculatorFind the original price before tax or discount, or the whole when you know a part and its percent.
Random pickers & passwords
- Spin the Wheel (random name picker)Type names or options, spin, and get a random winner. Yes/No, 1–10 and food templates.
- Random Number Generator (no repeats)Pick random numbers in any range — 1-10, 1-100 or custom — with or without repeats.
- Password Generator (strong & random)Strong random passwords of 8–128 characters, look-alike characters excluded, with strength and entropy.
Image tools
PDF tools (no upload)
- Merge PDF (combine PDF files)Combine several PDFs into one file in the order you want — without uploading them anywhere.
- PDF to JPG (PDF to image)Convert PDF pages to JPG or PNG images; choose pages and quality, download all as a ZIP.
- JPG to PDF (images to PDF)Turn photos and scans (JPG, PNG) into one PDF in your chosen order, with A4 fitting and auto rotation.
- Compress PDF (reduce file size)Shrink PDFs by recompressing the photos and scans inside, while keeping text searchable.
- Split PDF (extract pages)Extract selected pages, split by ranges, every N pages, or into single pages.
- Organize PDF (rearrange, rotate, delete pages)Rearrange, rotate and delete PDF pages with thumbnails, then save a new PDF.
- Add Page Numbers to PDFNumber every page (1, 2, 3 or 1 / 10) in the position you choose, optionally skipping the cover.
- Add Watermark to PDFStamp text like "COPY" or "CONFIDENTIAL" on every page — centered or tiled, any angle and opacity.
Everything is calculated in your browser. Nothing you type is stored or sent to a server.